This summer, ArtsBeat is inviting members of the theater world to contribute to the weekly Theater Talkback column, alternating with the critics Ben Brantley and Charles Isherwood. In the first guest post, Trav S. D., a historian of vaudeville, talked about the long bare-knuckles history shared between the boxing ring and the stage. This week, Alexis Soloski, a lecturer at Columbia University and a Times contributor, writes about memorable theatrical entrances (and a few exits).

With its reliance on pyro, flying rigs and muscled ensembles of backup dancers, the modern pop performance is the place to look these days for the dramatic stage entrance. Lady Gaga hatching from an egg or zip-lining to the stage above the heads of fans — now that’s a way to start a show.

Plays, by contrast, often begin with the actors already in situ, sprawled in the living room, say, or huddled on a park bench. Yet how a character arrives can tell us in the audience much about the play and how we ought to feel about it. Think of Lear staggering on with the body of his daughter, Agamemnon racing in on his chariot or Mary Tyrone drifting onstage in a morphine haze. Imagine for yourself the different moods created by tiptoeing surreptitiously through a half-open door; stamping on furiously from the wings; gliding down a wide staircase; or jogging in from the aisle, high-fiving patrons on the way.

Sara Krulwich/The New York TimesAnna Chlumsky, left, and Hannah Cabell in “3C.”

Though critics have recently scolded David Adjmi’s “3C,” a mordant take on the sitcom “Three’s Company” now at the Rattlestick Playwrights Theater, this dark comedy boasts the best entrance of the season. The play begins typically enough, with two roommates, Connie and Linda, discovered on the sofa the morning after a wild party. But after 15 minutes of desultory conversation, Brad, a leftover guest, suddenly bursts in from the kitchen, wild-eyed, confused and, save for a sock, completely naked.

Much screaming and mild injury ensues; a sense of real terror invades the sitcom setup. Abruptly, a play that has seemed merely loopy reveals itself as something stranger and darker. (Think of it as an attenuated, infinitely more frivolous version of the Angel’s entrance in “Angels in America,” an astounding moment that instantly alters the play’s world, tone, and story.)

Another recent favorite of mine occurred late in Edward Albee’s “Me, Myself & I,” which appeared at Playwrights Horizons in August of 2010. Though we were in Albee territory — where the rules of realism don’t hold sway — I wasn’t prepared for the moment when the stage floor parted to reveal a much-talked-about-but-never-seen character seated on a chariot heaped with emeralds and drawn by panthers. True theatrical delight.

For sheer verve, it’s hard to top Mark Rylance’s athletic, vodka-soaked, raw-egg-aided arrival in “Jerusalem” (not to mention the co-star who emerged from beneath the sofa cushions a beat later). That same season, though, Mr. Rylance was upstaged by his costar in “La Bête.” Playing a petulant princess, Joanna Lumley arrived in a terrifying haze of light and glitter, blown in from the wings, clutching a doll.

Contemporary directors have been known to take their cues from the pop world. John Tiffany, the Tony-winning director of “Once,” said he was influenced by the entrances of Pink and Justin Timberlake in fashioning Alan Cumming’s arrival as Dionysus in “The Bacchae” at Lincoln Center in July of 2008. The actor floated in from the flies upside-down, his golden kilt flapping.

Of course, if you run to your collected works of Euripides, you won’t find any mention of that descent — or of golden kilts. Oftentimes, a great entrance is an inspired creation of director and cast, such as Caliban rising impossibly from a trunk in the Bridge Project’s “Tempest” two years ago.

Sara Krulwich/The New York TimesAlan Cumming as Dionysus in the Lincoln Center Festival production of “The Bacchae” in 2008.

Many Greek and Renaissance dramas do call explicitly for remarkable appearances — and the occasional awesome egress. Think of Euripides’ Medea, who comes on at the end resplendent in the sun god’s chariot, drawn by dragons (take that, Albee’s panthers) or Christopher Marlowe’s Dr. Faustus dragged offstage by devils.

On the other hand modern and contemporary drama seem marked not so much by the traffic on and off the stage, but by its stalling. There’s Godot’s failure to enter in “Waiting for Godot” or Firs’s refusal to leave at the close of “The Cherry Orchard.”

The undisputed champs of the showy entrance fell between the Renaissance and modern times, in the form of 19th-century design geniuses. The actor and impresario Charles Kean created ghost traps that would allow spirits to rise and seem to float across the stage. Other innovations were the “vamp trap” (now revived on Broadway in the musical “Ghost”), which permits performers to materialize or disappear through seemingly solid matter, and the “star trap,” a specialty of pantomime, which propels actors on to the stage at great speed and with some small risk of impalement.

Would Madonna or Rihanna dare that?

Now I’ll exit, but it’s time for you to step in. Which stage arrivals have most pleased, surprised and alarmed you?